The subject matter disclosed herein relates to elevator systems. More particularly, the present disclosure relates to termination of suspension members of elevator systems.
A typical elevator system includes an elevator car, suspended by one or more suspension members, typically a rope or belt, that moves along a hoistway. The suspension member includes one or more tension members and is routed over one or more sheaves, with one sheave, also known as a drive sheave, operably connected to a machine. The machine drives movement of the elevator car via interaction of the drive sheave with the suspension member. The elevator system further typically includes a counterweight interactive with the suspension member. One or more of the ends of the suspension member are terminated, or retained in the hoistway.
Elevator rope or belt terminations typically rely on the ability to either wrap the rope or belt around a wedge, or the ability to spread the individual wires of the rope and create a knob by placing the spread wires into a socket and potting with a material such as a babbitt or epoxy-based potting compound. These typical methods do not work for suspension members that utilize tension members formed from or including unidirectional fibers in a rigid matrix. In such an arrangement, the tension member will fracture if bent around a typical wedge radius, and the fibers are not able to be spread and bent to be utilized in the potted arrangement. Methods of terminating the suspension member which do not require such deformation occupy significant amounts of space and require a relatively high clamping force to retain the suspension member. Such methods are prone to undertightening, resulting in slippage of the suspension member.
Thus, belts with such fiber tension members are typically terminated by capture of a substantially straight portion of the belt in a wedge-based termination. Manufacturing tolerances and other factors, however, make it difficult to ensure an even pressure distribution over a captured length of the belt. The belts have limited compressive strength, thus making it important to evenly distribute a clamping pressure to avoid pinching resulting in very high stresses in localized areas.